Thiokol Corporation

Donald C Giedt

Frank S Inman

Donald V Lushis

A braided preform fabrication for annular refractory articles such as an integral monolithic throat section and exit cone of a rocket motor nozzle is formed on a mandrel and includes closely spaced radially oriented carbon rods that extend to a uniform length from the mandrel surface and carbon fibers braided on the surface of the mandrel around the carbon rods in a triaxial braid whereby the fabrication has a 4-D fiber architecture. The density of the fabrication is increased by a process that is repeated four times and involves the steps of vacuum impregnation thereof with pitch, subjecting the impregnated preform to high pressure at a temperature that is gradually increased to about 700.degree. C. to convert the pitch to coke and to form the braided preform and mandrel into a billet, and producing graphitization of the braided preform by subjecting the billet to an argon atmosphere in a vacuum furnace at a temperature that is gradually increased to 2,500.degree. C. The mandrel is usually removed from the billet by machining after the second repetition of the process, but it may be removed at any time after the braided preform structure has acquired sufficient strength to withstand the temperature and pressure of further processing.

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Pleasant View, UT, United States of America

Donald C Giedt